Routing problem (possibly straightforward)

Discussion in 'Linux Networking' started by Rusty Phillips, Dec 13, 2003.

  1. eth0, the external interface is setup up as the gateway.
    eth1, the private, and internal interface is connected to the rest of the network -
    all routable addresses.

    The LAN machines all have public addresses in the same block, and I've tried setting either
    of the addresses (the internal inteface or the external one) as their gateway with no luck.

    Here's my routing table:
    Destination Gateway Genmask Flags Metric Ref Use
    Iface * U 0 0 0 eth1 * U 0 0 0 eth1
    loopback localhost.local UG 0 0 0 lo
    default (IT'S eth0's) UG 1 0 0 eth0

    Here's the netmasks:

    I also aliased eth1 to be part of the same subnet as eth0 and all the
    other public addresses (with the same netmask)

    Currently, my routing machine can see internet and LAN, but the local
    machines can only see each other, and the cards in the routing machine.

    For simplicity, assume that all packets are accepted - no firewall at all.
    This is how I tested the config to see that it's not working.

    Does anyone have any idea about what I need to do to get it working?
    Rusty Phillips, Dec 13, 2003
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  2. Rusty Phillips

    George Bell Guest

    Sorry if this sounds like a stupid question, but...
    You didn't say much about the hosts on your LAN.
    How are the routing tables on the machines on your LAN configured?
    Are they Linux/Windows/Other/Mixed?
    Do they point to this gateway as their default destination?

    George Bell, Dec 14, 2003
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  3. They are all strictly Windows machines, and they are set up as
    having the internal interface as their gateway.

    Each of these machines has a quota with the connection service
    (so NAT isn't a good option). HOWEVER, I have gotten around this
    by doing round-robin address assignment of the public IPs to the
    external interface and assigning all the other interfaces to private
    addresses. At least it works.

    It would be better, however, if I could assign each internal box
    it's own routable address.
    Rusty Phillips, Dec 15, 2003
  4. Hi
    I have a very similar problem except my internal network is through
    dial-in connections. I had this working under red hat 6 and 7 without
    problems but cannot seem to get it to work under redhat 9.0. I am starting
    to think that IP Forwarding is disabled by default in the kernel. Does
    anyone know if this is so?


    stewart menday, Dec 16, 2003
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